Information recording apparatus, information reproducing apparatus, and information distribution system

ABSTRACT

An information recording apparatus comprises an encryption section encrypting contents information and also a license condition referred to to limit use of the contents information and a decoding key for decoding the encrypted contents information to generate license information, and a recording section recording the encrypted contents information and the generated license information on a recording medium. An information reproducing apparatus comprises a decoder unit decoding the license information recorded on the recording medium using a second decoding key for decoding the license information and deciding on the basis of the license condition contained in the decoded license information whether the contents information can be used. If it is decided that the contents information can be used, the encrypted contents information recorded on the recording medium is decoded using the first decoding key contained in the decoded license information.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an information recordingapparatus for recording information on a recording medium such as a DVD,an information reproducing apparatus for reproducing informationrecorded on a recording medium such as a DVD, and an informationdistribution system including an information recording/reproducingapparatus for charging for use of information recorded on a recordingmedium or distributed through a network or by broadcasting.

[0002] In recent years, the advance of digital information processingtechnology and communication technology such as a broadband ISDN, andthe development of an advanced information recording medium such as aDVD which realizes a large capacity and high-quality image and sound areprogressing. Along with such development of a variety of advancedinformation transmission means, the circumstances are allowing users tomake use of an enormous number of digitized works which are distributedto the users through a network, a recording medium, or the like. Thesecircumstances increase opportunities for copies and alterations withoutpermission of authors or distribution unintended by authors, socopyright holders are anxious about infringement on their benefits.

[0003] An important challenge for wiping out such anxiety of copyrightholders is the development of a system which allows quick and easydistribution of digitized works and provides a fair digital informationusage environment assuming protection by copyright.

[0004] A DVD is a large-capacity personal computer medium replacing aCD-ROM, and various applications to movie, music, game, karaoke, and thelike can be expected. For popularization of DVDs, inexpensive DVD titlesor spread of a rental DVD market is expected. From these viewpoints aswell, it is essential to provide an information distribution systemassuming protection by copyright of information, i.e., a system based ona concept of charging not for possession of a digitized work recorded ona recording medium such as a DVD but for use of the digitized work.

BRIEF SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to provide aninformation recording apparatus, an information reproducing apparatus,and an accounting apparatus to constitute an information distributionsystem which allows quick and easy distribution of digitized works andprovides a digital information usage environment assuming protection bycopyright.

[0006] It is another object of the present invention to provide aninformation recording apparatus for quickly and easily distributingdigitized works which are distributed through a network or a recordingmedium and constituting a digital information usage environment assumingprotection by copyright by charging for use of digital information, anapparatus for reproducing the recorded information, and an accountingapparatus for charging for use of information.

[0007] According to an aspect of the present invention, there isprovided an information recording apparatus comprising an encryptionsection for encrypting contents information, a license informationgenerator for encrypting at least a license condition referred to limituse of the contents information and a decoding key for decoding theencrypted contents information to generate license information, and arecording section for recording the contents information encrypted bythe encryption section and the license information generated by thelicense information generator on a recording medium.

[0008] According to another aspect of the present invention, there isprovided an information reproducing apparatus comprising a storagesection for storing second decoding key information for decoding licenseinformation, a first decoder section for decoding the licenseinformation recorded on the recording medium using the second decodingkey stored in the storage section, a decision section for deciding, onthe basis of a license condition contained in the license informationdecoded by the first decoder section, whether contents information canbe used, a second decoder section for decoding the encrypted contentsinformation recorded on the recording medium using the first decodingkey contained in the license information decoded by the first decodersection when the decision section decides that the contents informationcan be used, and a reproduction section for reproducing the contentsinformation decoded by the second decoder section.

[0009] According to the information recording apparatus of the presentinvention, the encrypted contents information and the license conditionof the contents information are inseparately recorded on the recordingmedium. Only the information reproducing apparatus having an authenticdecoding key for decoding the license information can reproduce thecontents information recorded on the recording medium. In addition,since, before decoding, it is always decided on the basis of the licensecondition contained in the license information whether the contentsinformation can be used, use of the contents information under anillicit use condition is disabled. Therefore, digital informationassuming protection by copyright of the contents information can bequickly and easily distributed.

[0010] According to still another aspect of the present invention, thereis provided an accounting apparatus for charging for use of contentsinformation recorded on a recording medium, comprising an input sectionfor inputting a desired condition for use of the contents informationrecorded on the recording medium, a fee claiming section for claiming afee for use of the contents information on the basis of the conditioninput by the input section, and a recording section for, upon confirmingfee payment in response to the claim, recording, on the recordingmedium, license information containing at least a license condition forlimiting use of the contents information recorded on the recordingmedium on the basis of the condition input by the input section. Withthis arrangement, for the recording medium on which the contentsinformation and the license information containing the license conditionfor limiting use of the contents information are recorded, appropriatecharging for use of the contents information is enabled. In addition,digital information assuming protection by copyright of the contentsinformation can be quickly and easily distributed.

[0011] According to still another aspect of the present invention, thereis provided an accounting apparatus for charging for use of contentsinformation through a recording medium on which contents information andencrypted license information containing at least a license conditionreferred to to limit the use of the contents information are recorded,comprising a license information input section for inputting theencrypted license information recorded on the recording medium, adecoder section for decoding the encrypted license information input bythe license information input section, a condition acceptance sectionfor accepting a desired condition for use of the contents information, afee claiming section for claiming a fee for use of the contentsinformation on the basis of the condition accepted by the conditionacceptance section, a license information update section for, uponconfirming fee payment in response to the claim, updating the licenseinformation decoded by the decoder section, on the basis of thecondition input by the condition input section, an encryption sectionfor encrypting the license information updated by the licenseinformation update section, and an output section for outputting thelicense information encrypted by the encryption section. With thisarrangement, for the recording medium on which the contents informationand the license information containing the license condition forlimiting use of the contents information are recorded, appropriatecharging for use of the contents information is enabled. In addition,digital information assuming protection by copyright of the contentsinformation can be quickly and easily distributed.

[0012] According to still another aspect of the present invention, thereis provided a decision apparatus for deciding, on the basis of encryptedlicense information containing at least a license condition referred toto limit use of contents information and key information for decodingthe contents information, whether the contents information can be used,comprising a key generator for generating a public key used to encryptthe license information and a secret key for decoding the licenseinformation at a predetermined timing, the secret key corresponding tothe public key, a decoder section for decoding the input licenseinformation using the secret key generated by the key generator, adecision section for deciding, on the basis of the license conditioncontained in the license information decoded by the decoder section,whether the contents information can be decoded, and an output sectionfor outputting key information contained in the license informationdecoded by the decoder section when the decision section decides thatthe contents information can be used.

[0013] According to the present invention, since the secret parameterfor decoding the license information is generated in a decoder unit A ata predetermined timing and used only within a predetermined period,information security for the license information containing the licensecondition of the contents information and contents information decodingkey can be improved.

[0014] According to an update apparatus of the present invention, whichupdates license information on the basis of a request for updating thelicense information upon receiving at least a newly designated licensecondition and second key generation information necessary for generatingsecond key information from a decision device for deciding, on the basisof encrypted license information containing at least a license conditionreferred to to limit use of contents information, encrypted first keyinformation for decoding the contents information, and first keygeneration information necessary for generating the second keyinformation for decoding the encrypted first key information, whetherthe contents information can be used, the license condition and thefirst key generation information are updated, the second key informationis updated on the basis of the updated first key generation informationand the second key generation information, and the first key informationis encrypted using the updated second key information to generateencrypted license information containing at least the updated licensecondition, the first key information encrypted using the updated secondkey information, and the updated first key generation information.

[0015] According to the present invention, when the license informationis to be updated, the license information can be updated while ensuringthe information security without supplying the contents decoding key.

[0016] According to an update apparatus of the present invention, whichupdates license information on the basis of a request for updating thelicense information upon receiving at least a newly designated licensecondition, second key generation information necessary for generatingsecond key information, and an updated public key from a decision devicefor deciding, on the basis of the license information containing atleast a license condition referred to to limit use of contentsinformation, encrypted first key information for decoding the contentsinformation, and first key generation information necessary forgenerating the second key information for decoding the encrypted firstkey information, whether the contents information can be used, thelicense information being encrypted using a public key, the licensecondition and the first key generation information are updated, thesecond key information is updated on the basis of the updated first keygeneration information and the second key generation information, andthe first key information is encrypted using the updated second keyinformation to generate license information containing at least theupdated license condition, the first key information encrypted using theupdated second key information, and the updated first key generationinformation, and the generated license information is encrypted usingthe supplied public key.

[0017] According to the present invention, when the license informationis to be updated, the license information can be updated while ensuringthe information security without supplying the contents decoding key.

[0018] According to the present invention, there is provided aninformation usage apparatus which receives encrypted first keyinformation for decoding encrypted contents information and first keygeneration information necessary for generating second key informationfor decoding the first key information and decodes and uses the contentsinformation, wherein second key generation information necessary forgenerating the second key information for decoding the first keyinformation is held, the second key information is generated on thebasis of the second key generation information and the input first keygeneration information, and the encrypted contents information isdecoded using the generated second key information.

[0019] According to the present invention, since the decoding key (firstkey information) of the contents information is input to the informationusage apparatus while being kept encrypted, the information securitybetween the device for outputting the first key information and theinformation usage apparatus can be improved.

[0020] According to still another aspect of the present invention, thereis provided an information reproducing apparatus for reproducingcontents information from a recording medium on which encrypted contentsinformation and license information containing at least a licensecondition referred to to limit use of the contents information and firstkey information for decoding the contents information are recorded,comprising an instrument section for measuring a date and time, adecision section for deciding, on the basis of the date and timemeasured by the instrument section and the license information recordedon the recording medium, whether the contents information can be used,and an information reproduction section for, when the decision sectiondecides that the contents information can be used, decoding andreproducing the contents information recorded on the recording mediumusing the first key information output from the decision section,wherein information for notifying the decision section of the date andtime from the instrument section and the first key information outputfrom the decision section to the information reproduction section areencrypted.

[0021] According to the present invention, the security of informationto be transferred among the functional units (the instrument section,the decision section, and the information reproduction section) in theinformation generation device can be improved.

[0022] According to still another aspect of the present invention, thereis provided an information recording method of recording, on a recordingmedium on which at least encrypted contents information is recorded,encrypted license information containing at least a license conditionreferred to to limit use of the contents information and a decoding keyof the contents information, comprising transmitting information fordesignating second key information for encrypting first key informationfor encrypting the license information to a decision device for decidingwhether the contents information can be used, receiving, from theportable recording medium, the first key information for encrypting thelicense information, which is encrypted using the designated second keyinformation, and recording, on the recording medium, license informationgenerated on the basis of a designated license condition and encryptedusing the first key information.

[0023] According to the present invention, the contents informationrecorded on the recording medium cannot be normally decoded unless thedecision device which has been used to record the license information inthe recording medium is not used. Therefore, illicit use of the contentsinformation can be prevented.

[0024] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinbefore.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0025] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently preferredembodiments of the invention, and together with the general descriptiongiven above and the detailed description of the preferred embodimentsgive below, serve to explain the principles of the invention.

[0026]FIG. 1 is a block diagram showing the first arrangement of aninformation recording apparatus according to the first embodiment of thepresent invention;

[0027]FIG. 2 is a flow chart for explaining the operation of the firstinformation recording apparatus shown in FIG. 1;

[0028]FIG. 3 is a block diagram showing the second arrangement of theinformation recording apparatus according to the first embodiment of thepresent invention;

[0029]FIG. 4 is a flow chart for explaining the operation of the secondinformation recording apparatus shown in FIG. 3;

[0030]FIGS. 5A and 5B are views for explaining a method of separatingaccounting object information;

[0031]FIGS. 6A and 6B are views for explaining another method ofseparating accounting object information;

[0032]FIG. 7 is a block diagram showing the third arrangement of theinformation recording apparatus according to the first embodiment of thepresent invention;

[0033]FIG. 8 is a block diagram showing the first arrangement of aninformation reproducing apparatus according to the first embodiment ofthe present invention;

[0034]FIG. 9 is a block diagram showing an arrangement of a decoder unitshown in FIG. 8;

[0035]FIG. 10 is a flow chart for explaining the operation of the firstinformation reproducing apparatus shown in FIG. 8;

[0036]FIG. 11 is a flow chart for explaining the operation of thedecoder unit shown in FIG. 9;

[0037]FIG. 12 is a block diagram showing another arrangement of thedecoder unit having a clock for disabling time update;

[0038]FIG. 13 is a flow chart for explaining the operation of the clockof the decoder unit, which disables time update;

[0039]FIG. 14 is a flow chart for explaining the operation of thedecoder unit shown in FIG. 12;

[0040]FIG. 15 is a block diagram showing an arrangement of the clock ofthe decoder unit capable of updating time;

[0041]FIG. 16 is a flow chart for explaining the time update operationof the clock shown in FIG. 15;

[0042]FIG. 17 is a view showing a system constituted by a client and aserver to update time of the clock of the decoder unit through anetwork;

[0043]FIG. 18 is a block diagram showing an arrangement of a timesetting client shown in FIG. 17;

[0044]FIG. 19 is a block diagram showing an arrangement of a timesetting server shown in FIG. 17;

[0045]FIG. 20 is a flow chart for explaining the operation of the timesetting client shown in FIG. 18;

[0046]FIG. 21 is a flow chart for explaining the operation of the timesetting server shown in FIG. 19;

[0047]FIG. 22 is a flow chart for explaining the operation of the timesetting server shown in FIG. 19;

[0048]FIG. 23 is a block diagram showing an arrangement of a clockincorporated in the timesetting client shown in FIG. 18;

[0049]FIG. 24 is a flow chart for explaining the operation of the clockshown in FIG. 23;

[0050]FIG. 25 is a flow chart for explaining the operation of the clockshown in FIG. 23;

[0051]FIG. 26 is a block diagram showing an arrangement of aninformation reproducing apparatus (second information reproducingapparatus) having a function of updating license information andperforming charging;

[0052]FIG. 27 is a block diagram showing an arrangement of a decoderunit shown in FIG. 26;

[0053]FIG. 28 is a flow chart for explaining the operation of thedecoder unit shown in FIG. 27;

[0054]FIG. 29 is a block diagram showing an arrangement of a licenseinformation update client section shown in FIG. 26;

[0055]FIG. 30 is a flow chart for explaining the operation of thelicense information update client section shown in FIG. 29;

[0056]FIG. 31 is a block diagram showing an arrangement of a licenseinformation update server shown in FIG. 26;

[0057]FIG. 32 is a flow chart for explaining the operation of thelicense information update server shown in FIG. 31;

[0058]FIG. 33 is a view showing an example of contents of fee claimingfor use of accounting object information output from the licenseinformation update server;

[0059]FIG. 34 is a flow chart for explaining the operation of the entiresystem (the server and the client communicating with each other throughthe network) shown in FIG. 26;

[0060]FIG. 35 is a block diagram showing an arrangement of a licenseinformation update unit;

[0061]FIG. 36 is a flow chart for explaining the operation of thelicense information update unit shown in FIG. 35;

[0062]FIG. 37 is a flow chart for explaining the operation of thelicense information update unit shown in FIG. 35;

[0063]FIG. 38 is a block diagram showing an arrangement of an accountingapparatus for charging for use of accounting object information;

[0064]FIG. 39 is a block diagram showing an arrangement of a decoderunit in an information reproducing apparatus with a measure for anillicit copy of accounting object information (decision is made on thebasis of a decoder unit ID);

[0065]FIG. 40 is a flow chart for explaining the operation of thedecoder unit shown in FIG. 39;

[0066]FIG. 41 is a block diagram showing an arrangement of a licenseinformation update unit with a measure for an illicit copy of accountingobject information;

[0067]FIG. 42 is a flow chart for explaining the operation of thelicense information update unit shown in FIG. 41;

[0068]FIG. 43 is a block diagram showing another arrangement of thedecoder unit with a measure for an illicit copy of accounting objectinformation (decision is made on the basis of a decoder unit ID andmedium ID);

[0069]FIG. 44 is a flow chart for explaining the operation of thedecoder unit shown in FIG. 43;

[0070]FIG. 45 is a block diagram showing an arrangement of a copyingapparatus;

[0071]FIG. 46 is a flow chart for explaining the operation of thecopying apparatus shown in FIG. 45;

[0072]FIG. 47 is a block diagram showing an arrangement of a licenseinformation copy unit shown in FIG. 45;

[0073]FIG. 48 is a flow chart for explaining the operation of thelicense information copy unit shown in FIG. 47;

[0074]FIG. 49 is a block diagram showing an arrangement of aninformation reproducing apparatus (third information reproducingapparatus) according to the first embodiment of the present invention,which reproduces subsidiary information;

[0075]FIG. 50 is a block diagram showing an arrangement of the thirdinformation reproducing apparatus shown in FIG. 49;

[0076]FIG. 51 is a block diagram showing an arrangement of a decoderunit shown in FIG. 49;

[0077]FIG. 52 is a flow chart for explaining the operation of thedecoder unit shown in FIG. 51;

[0078]FIG. 53 is a block diagram showing an arrangement of aninformation distribution system using the information recordingapparatus and information reproducing apparatus of the presentinvention;

[0079]FIG. 54 is a block diagram showing an arrangement of a decoderunit A according to the second embodiment of the present invention;

[0080]FIG. 55 is a view showing an example of license information inputto the decoder unit A;

[0081]FIG. 56 is a view showing an example of updated information outputfrom the decoder unit A;

[0082]FIG. 57 is a flow chart for explaining the processing operation ofthe decoder unit A;

[0083]FIG. 58 is a flow chart for explaining the schematic procedure ofkey generation processing in a key holder section and key generationsection of the decoder unit A;

[0084]FIG. 59 is a block diagram showing an arrangement of a decoderunit B;

[0085]FIG. 60 is a view showing an example of license information inputto the decoder unit B;

[0086]FIG. 61 is a flow chart for explaining the processing operation ofthe decoder unit B;

[0087]FIG. 62 is a view showing an example of updated information outputfrom the decoder unit B;

[0088]FIG. 63 is a block diagram showing an arrangement of a decoderunit C;

[0089]FIG. 64 is a view showing an example of updated information outputfrom the decoder unit C;

[0090]FIG. 65 is a block diagram showing an arrangement of a decoderunit D;

[0091]FIG. 66 is a view showing an example of license information inputto the decoder unit D;

[0092]FIG. 67 is a flow chart for explaining the processing operation ofthe decoder unit D;

[0093]FIG. 68 is a flow chart for explaining the processing operation ofthe decoder unit D;

[0094]FIG. 69 is a view showing an example of updated information outputfrom the decoder unit D;

[0095]FIG. 70 is a block diagram showing an arrangement of a decoderunit D′;

[0096]FIG. 71 is a block diagram showing an arrangement of a licenseinformation update apparatus corresponding to the decoder unit A;

[0097]FIG. 72 is a flow chart for explaining the processing operation ofthe license information update apparatus shown in FIG. 71;

[0098]FIG. 73 is a block diagram showing an arrangement of a licenseinformation update apparatus corresponding to the decoder unit B;

[0099]FIG. 74 is a flow chart for explaining the processing operation ofthe license information update apparatus shown in FIG. 73;

[0100]FIG. 75 is a block diagram showing an arrangement of aninformation distribution system according to the third embodiment;

[0101]FIG. 76 is a block diagram showing another arrangement of theinformation distribution system according to the third embodiment;

[0102]FIG. 77 is a block diagram showing an arrangement of the main partof an information reproducing apparatus in which a decoding decisioncard is mounted;

[0103]FIG. 78 is a flow chart for explaining the processing operation ofthe information reproducing apparatus shown in FIG. 77 which is used inthe information distribution system shown in FIG. 75;

[0104]FIG. 79 is a block diagram showing an arrangement of the main partof the decoding decision card;

[0105]FIG. 80 is a flow chart for explaining the processing operation ofthe decoding decision card shown in FIG. 79;

[0106]FIG. 81 is a block diagram showing an arrangement of a timetransfer section in the decoding decision card shown in FIG. 79;

[0107]FIG. 82 is a block diagram showing an arrangement of acertification section in the time transfer section shown in FIG. 81;

[0108]FIG. 83 is a flow chart for explaining the processing operation ofthe certification section shown in FIG. 82;

[0109]FIG. 84 is a block diagram showing an arrangement of a contentskey transfer section in the decoding decision card shown in FIG. 79;

[0110]FIG. 85 is a block diagram showing an arrangement of acertification section in the contents key transfer section shown in FIG.84;

[0111]FIG. 86 is a flow chart for explaining the processing operation ofthe certification section shown in FIG. 85;

[0112]FIG. 87 is a block diagram showing an arrangement of a clock shownin FIG. 77;

[0113]FIG. 88 is a block diagram showing an arrangement of acertification section in the clock shown in FIG. 87;

[0114]FIG. 89 is a flow chart for explaining the processing operation ofthe certification section shown in FIG. 88;

[0115]FIG. 90 is a block diagram showing an arrangement of a decodingdecision section shown in FIG. 79;

[0116]FIG. 91 is a flow chart for explaining the processing operation ofthe decoding decision section shown in FIG. 90;

[0117]FIG. 92 is a block diagram showing an arrangement of aninformation reproduction section shown in FIG. 77;

[0118]FIG. 93 is a flow chart for explaining the processing operation ofthe information reproduction section shown in FIG. 92;

[0119]FIG. 94 is a block diagram showing an arrangement of acertification section in the information reproduction section shown inFIG. 92;

[0120]FIG. 95 is a flow chart for explaining the processing operation ofthe certification section shown in FIG. 94;

[0121]FIG. 96 is a block diagram showing another arrangement of theinformation reproduction section shown in FIG. 77;

[0122]FIG. 97 is a block diagram showing an arrangement of a licenseupdate apparatus;

[0123]FIG. 98 is a flow chart for explaining the processing operation ofthe license update apparatus;

[0124]FIG. 99 is a block diagram showing an arrangement of the main partof a decoding decision card as an interface with the update IF of thelicense update apparatus;

[0125]FIG. 100 is a flow chart for explaining the processing operationof the decoding decision card in updating the license;

[0126]FIG. 101 is a block diagram showing an arrangement of a licenseserver;

[0127]FIG. 102 is a flow chart for explaining the processing operationof the license server;

[0128]FIG. 103 is a block diagram showing a system configurationconstituted by a user terminal, a license server, and an electronicbanking apparatus in updating the license using electronic banking;

[0129]FIG. 104 is a block diagram showing an arrangement of a licenseupdate apparatus in the system configuration shown in FIG. 103;

[0130]FIG. 105 is a block diagram showing an arrangement of the licenseserver in the system configuration shown in FIG. 103;

[0131]FIG. 106 is a flow chart for explaining the processing operationof the entire system in updating the license in the system configurationshown in FIG. 103;

[0132]FIG. 107 is a block diagram showing an entire arrangement of aninformation reproduction system according to the fourth embodiment ofthe present invention;

[0133]FIG. 108 is a block diagram showing an arrangement of a licensedecision unit shown in FIG. 107;

[0134]FIG. 109 is a flow chart for explaining the processing operationof the information reproducing apparatus shown in FIG. 107;

[0135]FIG. 110 is a flow chart for explaining the processing operationof the information reproducing apparatus shown in FIG. 107;

[0136]FIG. 111 is a flow chart for explaining the processing operationof the information reproducing apparatus shown in FIG. 107 until licenseinformation is stored in a license database;

[0137]FIG. 112 is a flow chart for explaining the license informationdecoding key generation processing of the information reproducingapparatus shown in FIG. 107;

[0138]FIG. 113 is a view showing a structure of contents information;

[0139]FIG. 114 is a view showing a structure of license information;

[0140]FIG. 115 is a view showing an example of storage of licenseinformation in a license information database;

[0141]FIG. 116 is a view showing a structure of license updateinformation;

[0142]FIG. 117 is a view showing another example of storage of licenseinformation in the license information database;

[0143]FIG. 118 is a block diagram showing another arrangement of theinformation reproducing apparatus shown in FIG. 107;

[0144]FIG. 119 is a block diagram showing another arrangement of thelicense decision unit shown in FIG. 107;

[0145]FIG. 120 is a flow chart for explaining the operation of theinformation reproducing apparatus shown in FIG. 118 until encryptedlicense information and decoding key seed information are separated froma received broadcasting wave to generate a decoding key;

[0146]FIG. 121 is a view showing an example of the data structure of abroadcasting wave;

[0147]FIG. 122 is a block diagram showing an arrangement of aninformation distribution system according to the fifth embodiment of thepresent invention;

[0148]FIG. 123 is a view showing an example of data recorded on a rentaldisk;

[0149]FIG. 124 is a view showing an example of storage of a disk key ina contents database prepared in a center;

[0150]FIG. 125 is a view schematically showing the disk key distributionscheme in the information distribution system shown in FIG. 122;

[0151]FIG. 126 is a block diagram showing an arrangement of a licensecreation device;

[0152]FIG. 127 is a block diagram showing an arrangement of a licenseissuing device;

[0153]FIG. 128 is a block diagram showing an arrangement of a card;

[0154]FIG. 129 is a block diagram showing an arrangement of a cardadapter;

[0155]FIG. 130 is a block diagram showing an arrangement of a player;

[0156]FIG. 131 is a flow chart for explaining the disk informationcreation processing of the license creation device;

[0157]FIG. 132 is a view showing an example of storage of diskinformation in a license database in the license issuing device;

[0158]FIG. 133 is a view showing the schematic sequence of a disk keydistribution procedure in the information distribution system shown inFIG. 122 about subscription to a disk rental service, rental of a disk,and reproduction of contents;

[0159]FIG. 134 is a flow chart showing the disk key distributionprocedure shown in FIG. 133 in more detail;

[0160]FIG. 135 is a flow chart showing the disk key distributionprocedure shown in FIG. 133 in more detail;

[0161]FIG. 136 is a flow chart showing the disk key distributionprocedure shown in FIG. 133 in more detail;

[0162]FIG. 137 is a flow chart showing the disk key distributionprocedure shown in FIG. 133 in more detail;

[0163]FIG. 138 is a flow chart showing the disk key distributionprocedure shown in FIG. 133 in more detail;

[0164]FIG. 139 is a flow chart showing the disk key distributionprocedure shown in FIG. 133 in more detail;

[0165]FIG. 140 is a flow chart showing the disk key distributionprocedure shown in FIG. 133 in more detail;

[0166]FIG. 141 is a view showing the schematic sequence of another diskkey distribution procedure in the information distribution system shownin FIG. 122 about subscription to a disk rental service, rental of adisk, and reproduction of contents;

[0167]FIG. 142 is a flow chart showing the disk key distributionprocedure shown in FIG. 141 in more detail;

[0168]FIG. 143 is a flow chart showing the disk key distributionprocedure shown in FIG. 141 in more detail;

[0169]FIG. 144 is a flow chart showing the disk key distributionprocedure shown in FIG. 141 in more detail;

[0170]FIG. 145 is a flow chart showing the disk key distributionprocedure shown in FIG. 141 in more detail:

[0171]FIG. 146 is a flow chart showing the disk key distributionprocedure shown in FIG. 141 in more detail;

[0172]FIG. 147 is a flow chart for explaining encryption parameterupdate processing;

[0173]FIG. 148 is a flow chart for explaining encryption parameterupdate processing; and

[0174]FIG. 149 is a flow chart for explaining encryption parameterupdate processing.

DETAILED DESCRIPTION OF THE INVENTION

[0175] Embodiments of the present invention will be described below withreference to the accompanying drawing.

[0176] The entire configuration of an information distribution systemusing an information recording apparatus and information reproducingapparatus according to the first embodiment of the present inventionwill be briefly described first.

[0177]FIG. 53 shows an arrangement of an information distribution systemusing the information recording apparatus and information reproducingapparatus of the present invention. Referring to FIG. 53, a licenseinformation generation section 1002 and an information storage section1003 are equivalent to those shown in FIGS. 1, 3, 7, or the like, and adecoder unit 1013 is equivalent to that shown in FIGS. 9, 12, 27, 39,43, or the like. A reproduction section 1014 and a readout section 1012are also equivalent to those in the information reproducing apparatusshown in FIG. 8 or the like.

[0178] The operation of the entire system shown in FIG. 53 will bebriefly described below. Accounting object information is encrypted byan encryption key ke(1) (accounting object information ke(1)). First, adecoding key kd(1) of the accounting object information and a licensecondition such as an expiration date are input to the licenseinformation generation section 1002 (steps S701 and S702).

[0179] The license information generation section 1002 merges thedecoding key kd(1) with the license condition and then performsencryption using the encryption key ke to generate license informationand sends it to the information storage section 1003 (step S703). Theencrypted accounting object information is also input to the informationstorage section 1003 (step S704) and recorded on an information storagesection 1004 together with the license information (step S705).

[0180] The information storage section 1004 comprises a medium such as aDVD-ROM, a DVD-RAM, or a hard disk. Information recorded on this mediumis transferred to another medium (i.e., an information storage section1015) directly or through broadcasting or the Internet and read out bythe readout section 1012 in an information reproducing apparatus 1011(step S706). The readout license information is sent to the decoder unit1013 (step S707). The decoder unit 1013 holding the decoding key kdcorresponding to the encryption key ke decodes the license informationand extracts the decoding key kd(1) and license condition of theaccounting object information. The decoder unit 1013 checks the licensecondition to decide whether the accounting object information can beused. If the accounting object information is usable, the decoder unitoutputs the decoding key kd(1) to the reproduction section 1014 (stepS708). The reproduction section 1014 extracts the [accounting objectinformation] ke(1) from the readout section 1012 (step S709) and decodesit using the decoding key kd(1) to reproduce the accounting objectinformation.

[0181] The decoder unit 1013 holds the decoding key kd and an algorithmfor decoding license information. To avoid attack on security, thedecoder unit 1013 is preferably mounted not as software but as, e.g., anIC chip. In this case, the decoder unit 1013 comprises an IC chip havinga license information input section and an output section for outputtingthe decoding key of accounting object information (upon deciding thatthe accounting object information is usable). Decoding and decision ofthe use enable/disable condition are performed in the chip.

[0182] As one gist of the present invention, the license informationgeneration section 1002 merges the decoding key kd(1) of accountingobject information with the license condition and then performsencryption. Generally, encryption is performed/by scrambling informationbits to be encrypted. Therefore, once encryption is performed, twopieces of information which have simultaneously been encrypted cannot beseparated (without using decoding). It is important to disableseparation of accounting object information from the license conditionusing the nature of encryption.

[0183] In the above-described example, the accounting object informationis encrypted by the encryption key ke(1). Therefore,

[0184] 1. To use the accounting object information, the decoding keykd(1) is required. However, the decoding key kd(1) is encrypted intolicense information such that the decoding key and the license conditionare inseparable. Although the license information and the accountingobject information can be separated from each other, invalid licenseinformation does not contain the decoding key for properly decoding theaccounting object information, so “substitution” of license informationis meaningless.

[0185] 2. To obtain the correct decoding key kd(1), valid licenseinformation must be decoded. However,

[0186] 3. Only a proper decoder unit having the decoding key kd canperform this decoding.

[0187] 4. The proper decoder unit always refers to the license conditioncontained in the license information to decide the use enable/disablecondition. Therefore,

[0188] 5. In the apparatus including the license information generationsection and decoder unit of the present invention, the accounting objectinformation cannot be used under an invalid license condition inprinciple.

[0189] If the decoder unit 1013 decides that the accounting objectinformation cannot be used and does not output the decoding key kd(1),the license information must be updated or valid license informationmust be added to use the accounting object information. At this timing,accounting for the user of the information is generated. The user mustupdate the license information or acquire new license informationsomehow by a shop or vending machine or through the Internet. Anapparatus or vending machine set in a shop or a network server holds thedecoding key kd and the encryption key ke and therefore can decode thelicense information and rewrite and reencrypt the information so as toupdate the license information.

[0190] If the user wants to update the license information (or obtainnew license information), (one of) the license information added to theaccounting object information must be sent to an apparatus having alicense information update function.

[0191] 1′. Only a proper apparatus having the decoding key kd and theencryption key ke can decode/separate the decoding key kd(1) and thelicense condition of the accounting object information.

[0192] 2′. Only a proper apparatus having the decoding key kd and theencryption key ke can reencrypt the license information after therewrite of the license condition.

[0193] The updated license information is output from the licenseinformation update apparatus (a license information update clientsection 403 shown in FIG. 26, a license information update unit 603shown in FIG. 38, a license information update unit 702 shown in FIG.41, or a license information update unit 804 shown in FIG. 47) andreturned to the user's medium. The license information is kept encryptedoutside the license information update apparatus.

[0194] 3′. Since the license information has undergone encryption as acharacteristic feature of the present invention, the license conditioncannot be inadequately changed.

[0195] Generally, to transmit a decoding key through a network, thedecoding key is often reencrypted using another key. However, as thecharacteristic feature of the present invention, the decoding key kd(1)for decoding the encrypted accounting object information is merged withthe license condition and then encrypted. This provides a significanteffect in protection and charge for accounting object information suchas a work, as described above.

[0196] The arrangements and operations of the information recordingapparatus, the information reproducing apparatus, and the accountingapparatus of the present invention will be described below in detail.

[0197] (1) Information Recording Apparatus

[0198] (1-1) First Example of Information Recording Apparatus

[0199]FIG. 1 shows the first arrangement of an information recordingapparatus according to the present invention. More specifically, FIG. 1shows an arrangement of an information recording apparatus whichencrypts contents information (to be referred to as accounting objectinformation hereinafter) as an accounting object such as a digitizedwork, encrypts the license condition of the accounting objectinformation and a decoding key for decoding the encrypted accountingobject information to generate license information, and records theencrypted accounting object information and license information on apredetermined recording medium.

[0200] The information recording apparatus roughly comprises anaccounting object information input section 2, a license informationgeneration section 3, and a recording section 8.

[0201] Accounting object information is encrypted in advance using theencryption key ke(1) and input to the accounting object informationinput section 2. A decoding key corresponding to the encryption keyke(1) is the decoding key kd(1). Encryption of information X using anencryption key K will often be expressed as [X] k hereinafter, asneeded.

[0202] The license information generation section 3 is constituted by alicense condition input section 4, a decoding key input section 5, a keyholder section 6, and an encryption section 7.

[0203] The encryption key ke is stored in the key holder section 6 inadvance. This encryption key ke does not always agree with theencryption key ke(1).

[0204] A license condition is input to the license condition inputsection 4. The license condition includes at least one of the expirationdate of the accounting object information, the license information writetime, the contents ID, the medium ID, and the decoder unit ID.

[0205] The decoding key kd(1) corresponding to the encryption key ke(1),which is used to decode the encrypted accounting object information, isinput to the decoding key input section 5.

[0206] The license condition and the decoding key kd(1) are input to theencryption section 7 respectively through the license condition inputsection 4 and the decoding key input section 5. The license conditionand the decoding key kd(1) are merged.

[0207] After this, the merged license condition and decoding key kd(1)are encrypted using the encryption key ke stored in the key holdersection 6. Generally, encryption schema are roughly classified into apublic key scheme and a secret key scheme, and either can be employed.The encrypted data is called-license information. As the characteristicfeature of the encryption section 7, the license condition and theencryption key ke(1) are inseparably combined by merging and encryption.Therefore, an apparatus capable of decoding data encrypted using theencryption key ke, i.e., an apparatus having the decoding key kdcorresponding to the encryption key ke can exclusively separate thelicense condition from the encryption key ke(1). The decoding key kd(1)is a key for decoding the encrypted accounting object information, sothe accounting object information and the license condition areinseparably combined. The accounting object information and the licenseinformation as data can be always separated. However, without validlicense information, the accounting object information cannot be decodedto use the contents.

[0208] The recording section 8 writes the license information in aninformation storage section 9 and then writes the encrypted accountingobject information subsequent to the license condition.

[0209] The information storage section 9 may be a recording medium suchas a DVD-ROM, a DVD-RAM, or a hard disk. Such a recording medium havinginformation is set in a predetermined reproducing apparatus to reproducethe information. Alternatively, the information may be transferred fromthe information storage section 9 to another recording medium through anetwork such as the Internet or by broadcasting and reproduced by apredetermined reproducing apparatus.

[0210]FIG. 2 is a flow chart for explaining the operation of aninformation recording apparatus 1 shown in FIG. 1. First, the encryptedaccounting object information ke(1) is input to the accounting objectinformation input section 2 (step S1), the license condition is input tothe license condition input section 4 (step S2), and the decoding keykd(1) is input to the decoding key input section 5 (step S3). Theencrypted accounting object information is transferred from theaccounting object information input section 2 to the recording section 8(step S4), the license condition is transferred from the licensecondition input section 4 to the encryption section 7 (step S5), and thedecoding key kd(1) is transferred from the decoding key input section 5to the encryption section 7 (step S6). The encryption key ke held in thekey holder section 6 in advance is transferred to the encryption section7 (step S7). The encryption section 7 merges the license condition andthe decoding key kd(1) and then performs encryption using the encryptionkey ke to generate license information (step S8). The generated licenseinformation is transferred to the recording section 8 (step S9). Therecording section 8 merges the encrypted accounting object informationand license information and records them on the information storagesection 9 (step S10).

[0211] (1-2) Second Example of Information Recording Apparatus

[0212]FIG. 3 shows the second arrangement of an information recordingapparatus according to the present invention. More specifically, FIG. 3shows an arrangement of an information recording apparatus whichencrypts part of accounting object information as an accounting objectsuch as a digitized work together with a license condition to generatelicense information and records the remaining portion of the accountingobject information and license information in a predetermined recordingmedium. As in the first arrangement shown in FIG. 1, part of accountingobject information is encrypted together with a license condition toinseparately combine the accounting object information with the licensecondition.

[0213] The information recording apparatus roughly comprises a dataseparation section 12, a license information generation section 13, anda recording section 18.

[0214] The data separation section 12 divides accounting objectinformation into two parts. FIGS. 5A, 5B, 6A, and 6B show examples ofdata separation by the data separation section. For the descriptiveconvenience, a still picture will be exemplified, though this method canbe used for a motion picture and the like.

[0215] As shown in FIG. 5A, part (face regions in FIG. 5A) of a stillpicture may be extracted, and the face regions as shown in FIG. 5B maybe encrypted as part of license information. In this case, the image canbe seen without decoding the license information (i.e., without payingthe fee) although the image is partially omitted. As shown in FIG. 6A,an image is subjected to Fourier transformation to extract a frequencycomponent. A high-frequency component as shown in FIG. 6B may beencrypted as part of license information. In this case, unless thelicense information cannot be decoded (i.e., unless the fee is paid), noclear image can be obtained by reproducing the image with the frequencycomponent shown in FIG. 6A.

[0216] The license information generation section 13 is constituted by alicense condition input section 14, an encryption section 17, and a keyholder section 16.

[0217] The key holder section 16 stores the encryption key ke inadvance. The license condition input section 14 receives a licensecondition. The license condition includes at least one of the expirationdate of the accounting object information, the license information writetime, the contents ID, the medium ID, and the decoder unit ID. Thelicense condition is input to the encryption section 17 through thelicense condition input section 14. Part of accounting objectinformation, which is obtained by dividing the accounting objectinformation into two parts, is also input from the data separationsection 12 to the encryption section 17. The license condition and partof the accounting object information are merged and then encrypted usingthe encryption key ke stored in the key holder section 16 to generatelicense information.

[0218] The recording section 18 writes the license information in aninformation storage section 19 and then writes the remaining part of theaccounting object information, which is obtained by dividing theaccounting object information into two parts by the data separationsection 12, subsequent to the license information.

[0219] The information storage section 19 may be a recording medium suchas a DVD-ROM, a DVD-RAM, or a hard disk. Such a recording medium havinginformation is set in a predetermined reproducing apparatus to reproducethe information. Alternatively, the information may be transferred fromthe information storage section 19 to another recording medium through anetwork such as the Internet or by broadcasting and reproduced by apredetermined reproducing apparatus.

[0220]FIG. 4 is a flow chart for explaining the operation of aninformation recording apparatus 11 shown in FIG. 3. Accounting objectinformation is input to the data separation section 12 (step S21), andthe license condition is input to the license condition input section 14(step S22). The data separation section 12 divides the input accountingobject information into two parts (step S23), transfers one part of theaccounting object information to the encryption section 17 (step S24),and transfers the remaining part of the accounting object information tothe recording section 18 (step S25). The license condition istransferred from the license condition input section 14 to theencryption section 17 (step S26). The encryption key ke is transferredfrom the key holder section 16 to the encryption section 17 (step S27).The encryption section 17 merges the license condition and the part ofthe accounting object information transferred from the data separationsection 12 and then encrypts them to generate license information (stepS28). The generated license information is transferred to the recordingsection 18 (step S29). The recording section 18 merges the part of theaccounting object information transferred from the data separationsection 12 and the license information and records them on theinformation storage section 19 (step S30).

1. An information recording apparatus comprising: encryption means forencrypting contents information; license information generation meansfor generating encrypted license information containing at least alicense condition for limiting use of the contents information and adecoding key for decoding the contents information; and recording meansfor recording, on a recording medium, the contents information encryptedby said encryption means and the license information generated by saidlicense information generation means.
 2. An information recordingapparatus comprising: separation means for separating a part fromcontents information; license information generation means forgenerating an encrypted license information containing at least the partof information separated by said separation means and a licensecondition for limiting use of said contents information; and recordingmeans for recording, on a recording medium, the license informationgenerated by said license information generation means and the remainingpart of contents information.
 3. An information recording apparatuscomprising: recording information generation means for generatingencrypted recording information containing contents information and atleast a license condition for limiting use of the contents information;and recording means for recording the recording information generated bysaid recording information generation means on a recording medium.
 4. Aninformation reproducing apparatus comprising: means for receiving arecording medium on which encrypted contents information, and licenseinformation containing at least a license condition for limiting use ofthe contents information and first key information for decoding thecontents information are recorded; storage means for storing second keyinformation for decoding the license information; first decoding meansfor decoding the license information recorded on said recording mediumusing the second key information stored in said storage means; decisionmeans for deciding, on the basis of the license condition contained inthe license information decoded by said first decoding means, whetherthe contents information can be used; and second decoding means fordecoding the contents information recorded on said recording mediumusing the first key information contained in the license informationdecoded by said first decoding means when said decision means decidesthat the contents information can be used.
 5. An apparatus according toclaim 4, wherein the license condition contains at least an expirationdate of the contents information, and said decision means has instrumentmeans for measuring a date, and compares the date measured by saidinstrument means with the expiration date to decide whether the contentsinformation can be used.
 6. An apparatus according to claim 4, whereinthe license condition contains at least an expiration date of thecontents information, and said decision means has instrument means formeasuring a date and update disable means for disabling update of thedate measured by said instrument means, and compares the date measuredby said instrument means with the expiration date to decide whether thecontents information can be used.
 7. An apparatus according to claims 4,wherein the license condition contains at least an expiration date ofthe contents information, and said decision means has instrument meansfor measuring a date, reception means for receiving encrypted updateinformation for updating the date measured by said instrument means, andupdate means for decoding the encrypted update information received byaid reception means and updating the date measured by said instrumentmeans on the basis of the decoded update information, and compares thedate measured by said instrument means with the expiration date todecide whether the contents information can be used.
 8. An apparatusaccording to claim 4, wherein the license condition contains at least anexpiration date of the contents information and a recording date whenthe information has been recorded on said recording medium, and saiddecision means has instrument means for measuring a date, and comparesthe date measured by said instrument means, the expiration date, and therecording date with each other to decide whether the contentsinformation can be used.
 9. An apparatus according to claim 4, whereinsaid license condition contains at least a contents informationidentifier for identifying the contents information, and said apparatusfurther comprises request means for requesting fee payment for use ofcontents information corresponding to the contents informationidentifier when said decision means decides that the contentsinformation can be used, and update means for updating at least thelicense condition recorded on said recording medium when fee payment forthe request is confirmed.
 10. An apparatus according to claim 4, whereinthe license condition contains at least an expiration date of thecontents information, said apparatus further comprises license conditionupdate means for adding a decoder unit identifier of a unit capable ofdecoding the license information to the license condition when thelicense condition contains no decoder unit identifier for identifyingthe unit capable of decoding the license information, and said decisionmeans decides, on the basis of the expiration date and the decoder unitidentifier, whether the contents information can be used.
 11. Aninformation reproducing apparatus comprising: means for receiving arecording medium on which part of contents information and encryptedlicense information containing a least a license condition for limitinguse of the contents information and the remaining part of the contentsinformation are recorded; storage means for storing key information fordecoding the license information; decoding means for decoding thelicense information recorded on said recording medium using the keyinformation stored in said storage means; decision means for deciding,on the basis of the license condition contained in the licenseinformation decoded by said decoding means, whether the contentsinformation can be used; and reproduction means for synthesizing thepart of contents information contained in the license informationdecoded by said decoding means with the part of contents informationrecorded on said recording medium and reproducing the contentsinformation when said decision means decides that the contentsinformation can be used.
 12. An information reproducing apparatuscomprising: means for receiving a recording medium on which encryptedrecording information containing at least contents information and alicense condition for limiting use of the contents information isrecorded; storage means for storing key information for decoding therecording information; decoding means for decoding the recordinginformation recorded on said recording medium using the key informationstored in said storage means; decision means for deciding, on the basisof the license condition contained in the recording information decodedby said decoding means, whether the contents information can be used;and reproduction means for reproducing the contents information decodedby said decoding means when said decision means decides that thecontents information can be used.
 13. An information reproducingapparatus comprising: means for receiving a recording medium on whichencrypted contents information and license information containing atleast a license condition for limiting use of the contents informationand first key information for decoding the contents information arerecorded; instrument means for measuring a date; decision means fordeciding, on the basis of the date measured by said instrument means andthe license information recorded on said recording medium, whether thecontents information can be used; and information reproduction meansfor, when said decision means decides that the contents information canbe used, decoding and reproducing the contents information recorded onsaid recording medium using the first key information output from saiddecision means, wherein information for notifying said decision means ofthe date from said instrument means and the first key information outputfrom said decision means to said information reproduction means areencrypted.
 14. An information usage apparatus comprising: means forreceiving first key generation information necessary for generatingencrypted first key information for decoding encrypted contentsinformation; and means for holding second key generation informationnecessary for generating second key information for decoding the firstkey information, generating the second key information on the basis ofthe second key generation information and the input first key generationinformation, and decoding the encrypted contents information using thegenerated second key information.
 15. An information usage apparatuscomprising: means for receiving encrypted license information containingat least a license condition for limiting use of contents informationand first key information for decoding the contents information; firststorage means for storing a first secret parameter shared with a licenseinformation distribution device; first key generation means forgenerating second key information on the basis of the first secretparameter stored in said first storage means and a first publicparameter exchanged with said distribution device; first decoding meansfor decoding the received encrypted license information using the secondkey information generated by said first key generation means; decisionmeans for deciding, on the basis of the license condition contained inthe license information decoded by said first decoding means, whetherthe contents information can be used; and second decoding means fordecoding the contents information using the first key informationcontained in the license information decoded by said first decodingmeans when said decision means decides that the contents information canbe used.
 16. An apparatus according to claim 15, further comprisingsecond storage means for storing third key information for decodingfirst encryption information containing at least the first keyinformation and the license condition, the first encryption information,and second decoding means for decoding the first encryption informationcontained in the license information decoded by said decoding means,using the third key information stored in said second storage means. 17.An apparatus according to claim 15, wherein communication with saiddistribution device is performed through a recording medium having anarithmetic function.
 18. An apparatus according to claim 15, whereincommunication with said distribution device is performed through arecording medium having an arithmetic function, said apparatus furthercomprises third storage means for storing a second secret parametershared with said recording medium, reception means for receivingencrypted identification information of said recording medium from saidrecording medium, fourth key generation means for generating fourth keyinformation on the basis of the second secret parameter stored in saidthird storage means and a second public parameter exchanged with saidrecording medium, and third decoding means for decoding the encryptedidentification information received by said reception means using thefourth key information generated by said fourth key generation means,and said decision means decides, on the basis of the identificationinformation decoded by said third decoding means and the decoded licenseinformation, whether the contents information can be used.
 19. Arecording medium having an arithmetic function, on which encryptedlicense information containing at least a license condition for limitinguse of contents information and first key information for decoding thecontents information is recorded, comprising: first storage means forstoring a first secret parameter shared with a license informationrecording device and a second secret parameter shared with a decisiondevice for deciding on the basis of the license information whether thecontents information can be used; second storage means for storingidentification information given in advance; first key generation meansfor generating second key information on the basis of the first secretparameter stored in said first storage means and a first publicparameter exchanged with said recording device; first encryption meansfor encrypting the identification information using the second keyinformation generated by said first key generation means; second keygeneration means for generating third key information on the basis ofthe second secret parameter store in said first storage means and asecond public parameter exchanged with said decision device; secondencryption means for encrypting the identification information using thethird key information generated by said second key generation means; andtransmission means for transmitting the identification informationencrypted by said first and second encryption means to said recordingdevice and said decision device.
 20. A recording medium having anarithmetic function, on which encrypted license information containingat least a license condition for limiting use of contents informationand first key information for decoding the contents information isrecorded, comprising: first storage means for storing a first secretparameter shared with a license information recording device and asecond secret parameter shared with an information usage device whichuses the contents information on the basis of the license information;second storage means for storing identification information given inadvance; first key generation means for generating second keyinformation on the basis of the first secret parameter stored in saidfirst storage means and a first public parameter exchanged with saidrecording device; first encryption means for encrypting theidentification information using the second key information generated bysaid first key generation means; second key generation means forgenerating third key information on the basis of the second secretparameter stored in said first storage means and a second publicparameter exchanged with said information usage device; secondencryption means for encrypting the identification information using thethird key information generated by said second key generation means; andtransmission means for transmitting the identification informationencrypted by said first and second encryption means to said recordingdevice and said information using device.